Torsion Analysis - Lab Report Example

Unit 7: Torsion Test Lab Report By Lecturer’s and This lab report generally dwells on the torsion test that was carried out. A torsion test is a form of practical and procedural laboratory task that is aimed at measuring any material’s strength against maximum their twisting forces. This is a very common test often used in material mechanical segment for measuring the level of twist that a specific material can duly withstand before breaking or cracking. The applied pressure is hence termed as torque. Materials that are normally used within the manufacturing industries, including beams and metal fasteners, are frequently subject to this perspective of torsion testing mainly for the sake of determining their levels of strength especially under duress (AMERICAN SOCIETY FOR TESTING MATERIALS, 1961).  Torsion test may take place under three major categories. These includes; failure testing, operational testing, as well as proof testing. Failure testing has to do with the aspect of material twisting till it breaks (HELLER, 1975). Proof testing on the other hand plays a role of observing whether specific material can withstand a certain torque load quantity over a given timeframe. Finally, operational testing is meant for testing particular products for confirmation of their elastic limits before taking them to the market. It is often deemed very critical to take records of each and every torsion test result. This is done through creation of a stress-strain graph with both X-axis and Y-axis bearing the values regarding the angle of twist and the torque respectively. With use of a torsion testing device, twisting is done at quarter-degree level of increments with subsequent recording of the torque it can actually withstand. The twist angle corresponds to the strain, and the measured torque corresponds to the stress. Introduction: A torsion test is often conducted on various materials so as to determine their torsional features. These properties includes; Ductility, shear elasticity, ultimate and yield shear strengths, as well as the rapture modulus. Torsion test performance is mainly done for various distinct purposes and significance (KEETON, 1975). This is because, by testing products such as switches, biomedical catheter tubing, automotive steering columns, fasteners, among others; manufacturers gets the ability of simulating service conditions, checking of product quality, designs verification, and the aspect of ensuring adequate manufacturing techniques. The material’s elastic limit refers to the point upon which it will no longer return back to its unique size or shape. As determined by torsion test, elastic limit is taken as being equivalent to the line’s gradient from the on-set of testing all the way to proportional limit. This form of relationship was initially ascertained by Hooke’s law which states that; stress and strain are directly proportional till the proportional or elastic limit is attained, whereby the tested objects will begins to elicit some stress signs (KEETON, 1975).  After carrying out substantive tests, metal materials can then be categorized as either as being brittle or ductile. Often, ductile metals - including aluminium or steel - have higher stretch limits and hence can resist a lot of strain before any breakage. Brittle materials, including concrete and cast iron, have lower elastic limits hence require little strain before breakage. Failure to perform torsion test does not guarantee or allow for the release of materials to the market for industrial usage. It is hence very essential that the material’s ability to bear certain twisting level is measured accurately, so as to avoid any resultant mishaps with regards to their usage Experimental Procedures: The torsion test was undertaken under various procedural set-ups. First and for most, the test kick-started with the measuring the diameter and the overall length of the entire specimen. The line was then drawn down the extent of the sectional degree of the specimen by use of a pencil. This hence is used as a visual aid provider to the level of twist exerted on the specimen in the course of loading. The specimen was then mounted firmly within the testing machine with clear and adamant adherence to the stipulated procedures for using the torsion test equipment (SAUVEUR, 1938).  The operation of the testing machine involved various procedural steps. The spring balance was first allowed to hang freely from the torque arm as the balance was zeroed through adjustment of a small knurled bolt found at the upper right hand. Slide balancing, alongside the support framework, was then done till the two engraved distinct lines coincided. The hook balance was then slide beneath the torque arm’s knife edge with a hook freely hanging at its lower position. This was followed by the act of clamping the sample in to Torsion Machine’s jaws as the Torsiometer was fit to the sample. After firmly fixing the specimen, the straining head was then clamped to the bed. The straining head’s handle was then turned over and over again until a point where the torque arm lies in a horizontal position. The next task was the aspect of turning the spring balance’s hand wheel so as to elevate the entire balance up to the point whereby the hook contacts the torque arm’s knife edge. After that, the course and fine angular displacements on the straining head’s output and input shafts were then zeroed before the provision of a knurled nut behind each and every dial (PATIL, 2006). The revolution counter as well as the dial gauge was then zeroed by turning them in clockwise and a rotational manner respectively. Up to this point, the apparatus was then ready to be used, and hence the test samples were loaded based on the desirable increments. While testing more elastic materials, the torsion testing machine’s dial had to be periodically reset to the zero point. After all this, the results were then read and recorded accordingly regarding various elements. For instance, each level was recorded with regards to the specimen’s twist angle in degrees, as well as the applied torque in various distinct levels till it reaches the elastic limit. Apparatus: In this procedural experiment, a few essential apparatus were needed. These apparatus included the following: The Torsion testing machine Steel rule Micrometer screw gauge The specimen The figure below shows a standard torsion sample or specimen to be used with the testing machine: Results and graph: Table of Results: LOAD (N) TORQUE(T) (Nmm) Angle 1 Angle 2 Angle1-Angle2 (In Radians) In Degrees In Radians In Degrees In Radians 10 359.1 2.5 0.0436 0.1 0.0017 0.0419 20 718.2 4.8 0.0834 0.1 0.0017 0.0817 30 1077.3 6.9 0.1209 0.9 0.0157 0.1052 40 1436.4 9 0.1571 1 0.0175 0.1396 50 1795.5 11 0.1910 1.3 0.0227 0.1683 60 2154.6 13.5 0.2356 1.5 0.0262 0.2094 70 2513.7 15.9 0.2775 1.7 0.0297 0.2478 80 2872.3 18 0.3141 2 0.0349 0.2792 Graphical Presentation: Torsion (Nmm) verses Radian Discussion and Conclusion: From the above results and analysis, the Torsion strength can hence be attained by simply calculating the gradient of the Torsion verses radians line graph. This means that the torsion strength for our case= = = 10590.81 This generally shows that, the average torsion strength for the tested material is averagely 10590.81Torsion per Radian. This substance can hence be classified as being under the category of brittle substances since it resisted some breakage up to a greater extent. This is in contrast with the ductile substances or objects whereby a little strain exerted causes some sort of breakages. Reference List AMERICAN SOCIETY FOR TESTING MATERIALS. (1961). Symposium on shear and torsion testing. Philadelphia, American Society for Testing Materials. HELLER, R. A. (1975). Torsion. Made by Virginia Polytechnic Institute Film Unit. KEETON, R. (1975). Torsion. Made by Virginia Polytechnic Institute Film Unit. PATIL, N. (2006). Torsion test: an effective tool to evaluate wire ductility. [Beaumont, Tex.], Lamar University. SAUVEUR, A. (1938). The torsion test. Philadelphia, American Society for Testing Materials. Read More